[James West] has a young Doctor Who fan in the house and wanted to build something that could be played with without worrying about it being bumped and scratched. So, instead of creating a replica, [James] built a simple remote controlled K9 toy for his young fan.
K9 was a companion of the fourth Doctor (played by Tom Baker) in the classic Doctor Who series. He also appeared in several spin-offs. A robotic dog with the infinite knowledge of the TARDIS at hand, as well as a laser, K9 became a favorite among Who fans, especially younger children. [James] wanted his version of K9 to be able to be controlled by a remote control and be able to play sounds from the TV show.
Using some hand-cut acrylic, [James] built K9’s body, then started on plans for the motion control and brains. [James] selected the Raspberry Pi Zero for the controller board, a Speaker pHat for the audio, a couple of motors to move K9 around, and a motor controller. K9 is controlled by a WiiMote and has a button on his back to start pairing with the WiiMote (K9 answers with “Affirmative” when the pairing is successful.) When it came to the head, [James] was a little overwhelmed by trying to make the head in acrylic, so he got some foam board and used that instead. A red LED in the head lights up through translucent red acrylic.